Overview
EN ISO 22074-3:2024 - Railway infrastructure - Rail fastening systems - Part 3: Proof load test method for pull-out resistance (ISO 22074-3:2021) defines a laboratory test procedure to verify that the force required to pull a fastening insert or anchorage out of a sleeper or other supporting element exceeds a prescribed proof load. The standard applies to inserts that are cast into or glued into concrete, or screwed/attached into wood, polymeric composite or steel sleepers. Not applicable to embedded rails.
Key topics and technical requirements
- Test principle: Apply a vertical upward force to the anchored component until the prescribed proof load is reached, hold for 3 minutes, then remove the load. No damage that reduces system strength or durability should occur.
- Loading and equipment:
- Actuator capable of at least 25% more than the specified proof load.
- Force measurement equipment conforming to ISO 7500-1:2018, class 2.
- Linkage must apply vertical force directly above the anchored part without introducing unrepresentative moments.
- Loading rate and geometry:
- Load applied at a constant rate not exceeding 100 kN/min.
- Distance from load line to inner edge of supports: (100 ± 5) mm (with guidance for exceptions).
- If insert is inclined, load applied parallel to the insert axis; otherwise, normal to rail seat.
- Test specimens:
- Use complete sleepers or representative support blocks (for ballastless track) without modification.
- Concrete blocks shall have cube strength not greater than application concrete and no unexpected reinforcing close to the insert.
- Minimum block depth: embedded length of insert plus 15 mm (or adequate depth to avoid bending failure).
- Inspection and reporting:
- Inspect for any damage affecting integrity/durability.
- Test report must reference ISO 22074-3:2021 and include lab details, specimen description and test results.
Applications and users
- Ensures anchorage reliability for rail fastening systems in:
- Sleeper manufacturers (quality control of cast-in or glued inserts)
- Railway infrastructure owners and contractors (acceptance testing)
- Independent testing laboratories (type and production testing)
- Designers and product developers (validation of insert designs)
- Practical benefits: reduces risk of fastening failure, supports procurement specifications, and verifies compliance with performance requirements in the ISO 22074 series.
Related standards
- ISO 22074-1 - Vocabulary for rail fastening systems (referenced for terms).
- ISO 7500-1:2018 - Calibration and verification of force-measuring systems used in the test.
Keywords: EN ISO 22074-3:2024, rail fastening systems, proof load test, pull-out resistance, sleeper inserts, railway infrastructure, pull-out test method.
